FreedomPop has offered a free mobile phone service since last summer, bundling together 200 minutes, 500 text messages and 500 MBs of data. But in the buffet-loving U.S., the allure of the unlimited plan has a strong allure. So FreedomPop has decided to accommodate its customers who want all-you-can-eat voice and SMS.

On Monday, it launched a plan that includes unlimited calling and texting, plus 500 MBs of free data, for $4.58 a month. As with FreedomPop’s primary plan, customers can pay for more data à la carte, at $0.02 a megabyte, or subscribe to one of its larger paid data buckets.

According to CEO Stephen Stokols, the company now has half a million customers on its waiting list — and despite the fact that FreedomPop has quadrupled its customer service in order to activate as many of those customers as possible, it’s barely making a dent. Stokols said he hopes that the company will soon get to the point where it can activate tens of thousands of subscribers each week. In August, FreedomPop reported it had over 100,000 subscribers, but by the third or fourth quarter of 2014, the carrier plans to hit 500,000 customers, Stokols said.

Despite the backlog, FreedomPop doesn’t seem to see a reason to slow down its expansion plans. Today it began selling its second smartphone, the Samsung Galaxy S II, for $169, joining the $119 HTC Evo 4G. Both are WiMAX phones, but Stokols said FreedomPop plans to expand its portfolio in the coming quarters to LTE devices, including the Galaxy S III. By carrying a mix of cheaper WiMAX and relatively newer LTE phones, FreedomPop can appeal to different consumer segments, Stokols said.